L'élaboration des plans de gestion des réserves naturelles, bien plus qu'un simple exercice de style

International audienceLa parution en 1991 du premier Guide méthodologique des plans de gestion des réserves naturelles venait conclure près de cinq années de réflexion au sein de la Commission scientifique de la Conférence permanente des réserves naturelles (CPRN, 1991). En s'inspirant des travaux similaires menés sur les « management plans » des espaces protégés du Royaume-Uni (Wood, 1983 ; Nature Conservancy Council, 1988), ce travail avait comme objectif de transposer et d'adapter cette démarche au contexte des réserves naturelles et des autres espaces protégés français. La réalisation de ce guide méthodologique fut menée de front avec une validation grandeur nature sur 10 réserves naturelles et une réserve naturelle volontaire 1. Cette publication, accueillie avec un enthousiasme mitigé au sein du réseau des réserves naturelles et des réserves naturelles volontaires, correspondait pourtant à un réel besoin des gestionnaires. Il fallut attendre quatre années pour que la circulaire n°95-47 du 28 mars 1995, relative aux plans de gestion écologiques des réserves naturelles du ministère de l'Environnement, stipule la nécessité que chaque réserve naturelle soit dotée d'un plan de gestion écologique. Plus récemment, ce guide méthodologique a fait l'objet d'une mise à jour (Réserves naturelles de France, 1998). Depuis 1996, Réserves naturelles de France (RNF) est membre du Conseil national de protection de la nature et de son Comité permanent ; ses deux représentants successifs, Roger Estève puis Frédéric Bioret, ont participé à l'examen de nombreux plans de gestion au sein de cette instance. Actuellement, certaines réserves en sont à leur second, voire à leur troisième plan de gestion, mais seulement 73 2 des 150 réserves naturelles de France sont dotées d'un plan de gestion agréé par leur comité consultatif puis par le Conseil national de protection de la nature. Ce texte rassemble une série de commentaires, réflexions et conseils destinés aux gestionnaires de réserves et d'autres types d'espaces protégés, dans le but d'optimiser cet exercice qui peut sembler de prime abord fastidieux, contraignant et difficile

Potentialités de l'imagerie satellitaire Spot5 pour la cartographie de la végétation terrestre : application à l'île d'Ouessant (Finistère).

International audienceThe aim of this study is to test the Spot 5 satellite imagery for the cartography of terrestrial vegetation in the prospect of a monitoring of coastal zones. Two methods are used. The first method is based on a photointerpretation of a 2.5 meters multipectral image with the european EUNIS habitat classification. A comparison with aerial orthoimages is realised. The results show that Spot 5 satellite imagery is quite suitable for the vegetation mapping at a local scale. The majority of the habitats are identified with very few exceptions (patchy habitat of particular texture and of small size). The second method is based on the updating of existing data by the classification of the 10 meters multispectral image into a GIS. This process implies the development of a vegetation dynamic model. A map is produced in a short delay. It may be useful for the large-scale monitoring of dynamic vegetation processes.Les auteurs ont pour objectif de tester l'utilisation d'images du satellite Spot 5 pour la cartographie et l'inventaire de la végétation terrestre, dans la perspective d'un suivi régulier du littoral en complément des données aériennes. Ils mettent en œuvre deux méthodes. La première est fondée sur la photo-interprétation d'une image multispectrale à 2,5 mètres de résolution spatiale en adoptant la nomenclature européenne de description des habitats EUNIS. La comparaison des supports satellitaire et aérien (orthophotographies de l'IGN) est réalisée. L'image Spot 5 convient comme support à la cartographie des habitats naturels et semi-naturels sauf pour la détection de certaines entités de petite taille et de texture particulière (saulaie, prunelliers) facilement repérables sur l'orthophotographie. La seconde méthode est fondée sur la mise à jour semi-automatique d'un inventaire cartographique ancien par la classification de l'image multipectrale Spot 5 à 10 mètres de résolution. Impliquant le développement d'un modèle d'évolution du couvert végétal, la méthode fournit une carte dans un délai relativement court qui peut servir utilement de support à la phase de terrain

Response of breeding European Storm Petrels to habitat change

International audienceMainly through trampling and manuring, ground-nesting seabirds induced significant habitat changes both on vegetation cover and soil in one of the largest French colonies of European Storm Petrel , Habitat deterioration led to a high level of erosion and the collapse of many former Rabbit burrows previously occupied by breeding Storm Petrels. The loss of burrows accelerated in recent years since Great Cormorants bred on the islet with growing numbers. The main consequence of this disturbance was at first shifting of breeding Storm Petrels from burrows to rocky sites, reflecting some behavioral plasticity to buffer environmental variability. But over 18 years, a significant decrease in breeding numbers of Storm Petrels was recorded and attributed to continuous nest site destruction. Thus, other behavioral responses were also suspected, such as temporary non-breeding or emigration of birds that have to find a new nest site. Such a problem of heavy erosion and loss of nesting habitat could induce serious detrimental effects on burrowing seabirds breeding in a limited number of colonies

Ecology and phytosociology of endangered psammophytic species of the Omphalodes genus in western Europe

Omphalodes kuzinskyanae Willk. is an endangered annual plant of the family Boraginaceae, endemic to a narrow coastal area in the Lisbon region (Portugal). Omphalodes littoralis Lehm. occurs in northwest Spain (subsp. gallaecica) and northwest France (subsp. littoralis). Three approaches were used to assess the ecological requirements of O. kuzinskyanae: (1) physical and chemical characterization of their habitat soil; (2) phytosociological analysis; (3) comparison of several life history parameters under different light conditions. Germination experiments were conducted to evaluate seed dormancy. The results show that O. kuzinskyanae occurs in thin sandy soil with a substantial amount of organic matter and clay, mostly over limestone pavements. Phytosociological analysis shows that O. kuzinskyanae occurs both in sciophytic and heliophytic communities. Life history comparisons demonstrated that this plant has a strong preference for sciophytic conditions: under strong shade, plants have a higher survival rate, attain a greater height and width, and produce approximately nine times more seeds than in sunny conditions. In contrast with O. kuzinskyanae, published data on O. littoralis indicate that this species occurs in heliophytic conditions. This group of Omphalodes is possibly limited both in geographical distribution and habitat by its vulnerability to hydric stress. Scenarios are discussed that can explain the extensive gap separating the present ranges of the two species and their ecological differences. We propose two new syntaxa: Linario arenariae-Omphalodetum littoralis, Geranio purpurei-Galietum minutuli omphalodetosum kuzinskyana

Phytoecological Study, Ethnobotanical and Dynamic of Dry Vegetation in the Ngazidja Island, Comoros Archipelago

The dry vegetation of Ngazidja, Comoros Islands, is very rich in biological diversity. However, it is the most threatened and least known in this island. The purpose of this study is to provide ecological information about dry vegetation and to elaborate proposals for conservation. Data collection is ecological surveys, and ethnobotanical and socioeconomic surveys. Several floristic, and structural and soil parameters were processed and analyzed to characterize the sites. Five types of dry vegetal formations are identified: the dry forests of Lac-salé, Ngouni-Hamboda and Infoundihé-Chambouani, and the dry thickets of Singani, Domoni-Amboini, Hahaya. Eighteen surveys of 10 transects were undertaken. The forests are well stratified and the trees do not exceed 15 m high, with deciduous leaves. The density varies from 500 to 800 individuals per hectare in forest against 310 to 165 in thicket. A total of 103 species, belonging to 46 families, were recorded in these formations, including 70 trees and shrubs. Natural regeneration is only good for thickets and the dry forests of Lac salé and Infoundihé-Chambouani. Sustainable alternative solutions are proposed in order to improve the socioeconomic living conditions of the population and the conservation of biodiversity

La restauration des végétations des hauts de falaises du littoral atlantique, vers une évaluation globale

Les végétations des falaises littorales atlantiques ont fortement été dégradées par une fréquentation touristique croissante. Cet article nous présente les étapes essentielles à la réussite écologique et socio-économique des opérations de restauration, qui passe par une meilleure connaissance de la diversité des écosystèmes et des modes de gestion

La végétation des sources thermominérales salées d’Auvergne

The authors accomplish a phytosociological study of the salt thermomineral spring vegetation in Auvergne. They follow a ‘braun-blanqueto-tüxenian’ approach of the association. Despite a large number of relevés carried out on the salty sites of Auvergne, the communities stay unknown as it seems necessary to synthesize them and clarify their phytosociological status.The authors carry out an analysis and a synthesis of 176 phytosociological relevés illustrating the communities of the twenty salty localities known in Auvergne. From 16 sites, 69 relevés were specifically produced as part of this study.Nine communities are presented on the floristical and synecological plan : three new associations and six new sub-associations are described.Les auteurs réalisent une étude phytosociologique de la végétation des sources thermominérales salées d’Auvergne, en s’inscrivant dans une approche «braun-blanqueto-tüxenienne» de l’association. Malgré un grand nombre de relevés réalisés sur les sites salés d’Auvergne, les groupements restent méconnus et il semblait nécessaire d’en réaliser la synthèse pour en préciser le statut phytosociologique.Après une rapide présentation du contexte physiographique des localités étudiées et un bref rappel des travaux phytosociologiques antérieurs, les auteurs réalisent une analyse et une synthèse de 176 relevés phytosociologiques illustrant les communautés de la vingtaine de localités salifères connues en Auvergne. Provenant de 16 sites, 69 relevés ont été spécifiquement réalisés dans le cadre de cette étude.Neuf groupements de rang association sont présentés sur le plan floristique et synécologique : trois associations et six sous-associations nouvelles sont décrites

Contribuição para o conhecimento das comunidades vegetais de Welwitschia mirabilis (Welwitschiaceae, Gnetophyta) do deserto do Namibe (Angola)

A Welwitschia mirabilis é uma planta antiga, com uma morfologia e ecologia divergentes no âmbito das gimnospérmicas atuais. É endémica – e a espécie símbolo – do deserto do Namibe, o deserto mais antigo da Terra. Fazemos um estudo da estrutura florística e da sinecologia das comunidades vegetais W. mirabilis no território angolano. Concluímos existirem 4 comunidades distintas: (i) uma comunidade associada a linhas de água efémeras dominada por Acacia reficiens e Boscia pestalozziana; (ii) uma segunda comunidade, floristicamente pobre, dominada por W. mirabilis, de áreas secas e planas com sedimentos heterométricos nos interflúvios; (iii) uma terceira comunidade associada a sedimentos arenosos dominanda por gramíneas perenes; (iv) e, por último, uma comunidade dominada por espécies do género Commiphora (Burseraceae), própria dos sectores basais de inselbergs xistosos e/ou grauvaquicos.Welwitschia mirabilis is an ancient plant with a divergent morphology and ecology from other gymnosperms. It is a symbol and an endemic species of the Namib Desert, the oldest desert on Earth. We studied the floristic structure, the phytosociology and synecology of the plant communities dominated by W. mirabilis in Angolan territory. We conclude that there are 4 distinct communities: (i) a community associated with ephemeral watercourses dominated by Acacia reficiens and Boscia pestalozziana; (ii) a second community, floristically poor, dominated by W. mirabilis, from dry and flat Interfluvial areas with heterometric sediments; (iii) a third community associated with sandy sediments dominated by perennial grasses; (iv) and a community dominated by Commiphora species (Burseraceae), typical of the basal sectors of schist or greywackes residual reliefs (inselbergs).info:eu-repo/semantics/publishedVersio

Reserva Natural de Santa Luzia (Cabo Verde): Guia Ilustrado da Flora e Vegetação

info:eu-repo/semantics/publishedVersio

Phenotypic differentiation among native, expansive and introduced populations influences invasion success

Aim: Humans influence species distributions by modifying the environment and by dispersing species beyond their natural ranges. Populations of species that have established in disjunct regions of the world may exhibit trait differentiation from native populations due to founder effects and adaptations to selection pressures in each distributional region. We compared multiple native, expansive and introduced populations of a single species across the world, considering the influence of environmental stressors and transgenerational effects. Location: United States Gulf and Atlantic coasts, United States interior, European Atlantic and Mediterranean coasts, east coast of Australia. Taxon: Baccharis halimifolia L. (eastern baccharis). Methods: We monitored seed germination, seedling emergence, survival and early growth in a common garden experiment, conducted with over 18,200 seeds from 80 populations. We also evaluated the influence of environmental stress and maternal traits on progeny performance. Results: Introduced European Atlantic populations had faster germination and early growth than native populations. However, this was not the case for the more recently naturalized European Mediterranean populations. Introduced Australian populations grew faster than native populations in non-saline environments but had lower survival in saline conditions commonly encountered in the native range. Similarly, expansive inland US populations germinated faster than coastal native populations in non-saline environments but grew and germinated more slowly in saline environments. Maternal inflorescence and plant size were positively related with seed germination and seedling survival, whereas flower abundance was positively correlated with seedling early growth and survival. However, maternal traits explained a much lower fraction of the total variation in early demographic stages of B. halimifolia than did distributional range. Main conclusions: Phenotypic differentiation could allow B. halimifolia to adapt to different biotic and abiotic selection pressures found in each distributional range, potentially contributing to its success in introduced and expansive ranges